# Isometric 3d collision detection [duplicate]

I'm making an isometric map for a game, I can draw it, but I don't know how to implement a sort of 3d collision detection without Threejs or other 3d library.

It is possible? Maybe make the block an Object can help? I have searched a lot on the web, but I found only libraries. Thank you!

This is my JavaScript code:

var canvas = document.getElementById('canvas'),
ctx = canvas.getContext('2d'),
width = canvas.width = window.innerWidth,
height = canvas.height = window.innerHeight,
stop = false;

var tw, th;
var player;

setup();
draw();

function setup(){
ctx.translate(width/2,50);

tw = 60; //tile width
th = 30; // tile height
player = new Player(2,3,2);

};

function draw(){

ctx.clearRect(-width/2,-50,width*1.5,height+50);

for(var i = 0; i < 5; i++){
for(var j = 0; j < 5; j++){
drawBlock(i,j,1,tw,th);
}
}

if(!stop){
requestAnimationFrame(draw);
}
}

function drawBlock(x,y,z,w,h){

var top = "#eeeeee",
right = '#cccccc',
left = '#999999';

ctx.save();
ctx.translate((x-y)*w/2,(x+y)*h/2);

ctx.beginPath();
ctx.moveTo(0,-z*h);
ctx.lineTo(w/2,h/2-z*h);
ctx.lineTo(0,h-z*h);
ctx.lineTo(-w/2,h/2-z*h);
ctx.closePath();
ctx.fillStyle = "black";
ctx.stroke();
ctx.fillStyle = top;
ctx.fill();

ctx.beginPath();
ctx.moveTo(-w/2,h/2-z*h);
ctx.lineTo(0,h-z*h);
ctx.lineTo(0,h);
ctx.lineTo(0,h);
ctx.lineTo(-w/2,h/2);
ctx.closePath();
ctx.fillStyle = "black";
ctx.stroke();
ctx.fillStyle = left;
ctx.fill();

ctx.beginPath();
ctx.moveTo(w/2,h/2-z*h);
ctx.lineTo(0,h-z*h);
ctx.lineTo(0,h);
ctx.lineTo(0,h);
ctx.lineTo(w/2,h/2);
ctx.closePath();
ctx.fillStyle = "black";
ctx.stroke();
ctx.fillStyle = right;
ctx.fill();

ctx.restore();

}

function drawTile(x,y,stroke,col){

ctx.save();
ctx.translate((x-y)*tw/2,(x+y)*th/2);

ctx.beginPath();
ctx.moveTo(0,0);
ctx.lineTo(tw/2,th/2);
ctx.lineTo(0,th);
ctx.lineTo(-tw/2,th/2);
ctx.closePath();
if(stroke){
ctx.stroke();
}else{
ctx.fillStyle = col;
ctx.fill();
}

ctx.restore();

}

function Player(x,y,z){
this.x = x;
this.y = y;
this.z = z;
this.w = 10; //width
this.h = 10; //height
}
canvas{
width:100%;
height:100%;
}
<canvas id="canvas"></canvas>

• It's not really clear, to me at least, what your goal is. Could you compare it to some existing game perhaps? Aug 25, 2017 at 3:25
• Are you sure you need 3d collision detection? If you are making a tile based game and dont care about collisions on the y-axis, you could either just do 2d collisions. An even easier approach, since it is a tile-based game, would be to just check if objects are on a specific tile Aug 25, 2017 at 8:37
• When I developed an isometric game once, I made a good experience with keeping the game mechanics completely orthogonal and do the conversion to isometric in the rendering system. This drastically reduced the mental acrobatics I had to do when implementing things like collision detection and movement vectors. Nov 10, 2018 at 12:25

method boolean checkCornerColission(x1, y1, z1, x2, y2, z3, width, height, depth):